Jeremy Stoppelman, CEO of Yelp, told the Telegraph earlier this month that he was unhappy with the way Google took reviews from Yelp users to display on its Google Places results. He said he had asked Google to stop this but was told the only way would be for Yelp and similar services to be removed from Google’s search index entirely.

Speaking at the South By Southwest (SXSW) technology conference in Austin, Texas, Mayer said: “We actually send a lot of traffic to Yelp and Trip Adviser and other review sites.”

She said that Google had not issued an ultimatum but that the search giant has “one core index for all our locations”. She added: “It is very difficult to take them out of one index and not another because those indices are actually the same.”

In her presentation on the future of mobile and location, Mayer said that around 40 per cent of all Google Maps use is mobile. She said that every day around 35 million miles are driven by motorists using Google Maps navigation.

She said that in future Google will be able to go much further, particularly using “contextual discovery”. Mayer gave the example of a smartphone that would consult your calendar to suggest possible flights you could take for a forthcoming business trip, deliver the weather forecast and even consult live travel updates to tell you when to leave for the airport.